Abstract

RADICE, Stefania et al. Microfábricas de deformación del basamento metamórfico, sector centro-oriental de la Sierra de Comechingones, Córdoba. Rev. Asoc. Geol. Argent. [online]. 2015, vol.72, n.2, pp.157-166. ISSN 0004-4822.

The goal of this paper is to present an objective analysis of micro-deformational fabrics observed in the basement exposed in the center-east of the sierra de Comechingones. This basement is a metamorphic complex consisting mainly of metatexites, diatexites and minor bodies of gneisses rich in biotite and garnet, amphibolites, phyllonites, including small outcrops of marbles, and pegmatites. The assemblage of microstructures and microtextures developed during metamorphism and migmatization (poikiloblastic and symplectite textures) together with intracrystalline microstructures related to deformational stages (mechanical twinning, kinking, diffusion creep, recovery, among others) can be used to find the mechanisms and thermobarometric conditions that took place in the studied metamorphic complex. On this basis, the geological history of the complex has been divided in three stages. A first event M1 - D1 was developed in medium-grade conditions in almandineamphibolite facies (6 kbar - 630 °C). A second regional event M2 - D2, associated with the metamorphic peak, occurred in high grade amphibolite to granulite facies (7,5 kbar and 750 °C). Finally, a third dynamic event M3 - D3 was developed, first in ductile phase (5 kbar, 640 °C) followed by a ductile-fragile stage (3,5 a 4 Kbar y 400 - 450 ºC).

Keywords : Microtextures; Microstructures; Metamophism; Deformation; Sierra de Comechingones.

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